Prosody is the systematic study of meter, rhythm, and intonation of language found in poetry, but also in prose.
From A Poet’s Glossary
The following definition of the term prosody is reprinted from A Poet’s Glossary by Edward Hirsch.
The word prosody is the anglicized form of the Latin word prosodia (accent of a syllable), which derives from the Greek prosōidia (a song sung to instrumental music). Prosody is the systematic art or study—the notation, principles, and theory—of versification. It especially refers to aspects of musicality, such as rhythm and sound (alliteration, assonance, euphony, onomatopoeia, and so forth), but can also include the study of such things as structure and rhetoric. Linguistic prosody is the study of these elements in ordinary language. Literary prosody, which is also known as metrics, is the study of them in the literary arts.
See also meter.